Climate Change
For current and
future climatological effects of human influences, see global warming.
For the study of past climate change, see paleoclimatology.
For temperatures on the longest time scales, see geologic temperature record.
Climate change is a significant and lasting change in the
statistical distribution of weather patterns over periods ranging from decades to
millions of years. It may be a change in average weather conditions, or in the
distribution of weather around the average conditions (i.e., more or fewer
extreme weather events). Climate change is caused by factors that include
oceanic processes (such as oceanic circulation), variations in solar radiationreceived
by Earth, plate tectonics and volcanic eruptions, and human-induced
alterations of the natural world; these latter effects are currently causingglobal warming,
and "climate change" is often used to describe human-specific
impacts.
Scientists actively work to understand past and
future climate by using observations and
theoretical models. Borehole temperature profiles, ice cores,
floral and faunal records, glacial and periglacial processes, stable isotope
and other sediment analyses, and sea level records serve to provide a climate
record that spans the geologic past. More recent data are provided by the
instrumental record. Physically based general circulation modelsare often used
in theoretical approaches to match past climate data, make future projections,
and link causes and effects in climate change.
